Variable timing cam follower



Dec. 22, 1953 ,J. R. HUTCHISON 2,663,283

VARIABLE TIMING CAM FOLLOWER Filed Sept. 2, 1952 INVENTOR.

JAMES R. HUTCHISON BY 151m: & 161ml AGENTS Patented Dec. 22, 1953 2"".-

VARIABLE TIMING CAM FOLLOWER James R. Hutchison, Palm City, Calif-2,assignor of one-half to Loyd F. Ashley, Chula Vista,

Calif.

Application September 2, 1952, Serial No. 307,500

. 4 Claims.

The present invention relates generally to valve operation and moreparticularly to a variable timing cam follower for use with poppet typevalves.

The primary object of this invention is to provide avariable timing camfollower for use with poppet type valves in which the opening andclosing points of the valves and the period of opening of the valves maybe adjusted.

Another object of this invention is to provide a variable timing camfollower of the type de scribed in which the timing of the valves may beadjusted while the mechanism is in operation.

Another object of this invention is to provide a variable timing camfollower of the type described in which the adjustment of the valves maybe automatically controlled or controlled by the operator.

Another object of this invention and this disclosure, ancillary to theimmediately preceding object, is to teach the best known mode ofcarrying the invention into actual practice.

Another object of this invention is to provide a variable timing camfollower which is adapted for fabrication from many different materials,so that the choice of material can be according to the dictates ofavailability and price considerations, the exact sizes and proportionsbeing matters easily determined to suit particular conditions and needs.

Finally, it is an object to provide a variable timin cam follower of theaforementioned character which is simple, safe and convenient tooperate, and which will give generally eflicient and durable service.

With these and other objects definitely in view, this invention consistsin the novel construction, combination and arrangement of elements andportions, as will be hereinafter fully described in the specification,particularly pointed out in the claims, and illustrated in the drawingwhich forms a material part of this disclosure and wherein similarcharacters of reference indicate similar or identical elements andportions throughout the specification and throughout the views of thedrawing, and in which:

Fig. 1 illustrates diagrammatically the cam follower as adapted to aninternal combustion engine;

Fig. 2 is a fragmentary view of an internal combustion engine showingthe method of adjusting the cam followers;

Fig. 3 is a diagrammatic sectional View of a cam in contact with a camfollower;

Fig. i is a diagrammatic sectional view of a cam in contact with a camfollower which has been rotated through 90 from the position shown inFig. 3.

Fig. 5 is a fragmentary sectional view of the cam follower as installedin an engine; and

Fig. 6 is a view taken on the line iil3 of Fig. 5.

Referring now to the drawing in detail, Fig. 1 illustrates a section ofan internal combustion engine, generally indicated by the numeral it, inwhich the valve I2 is operated by means of a valve lifter it which hasat one end a cam follower it and at the other end a threaded button it?retained in position by means of a loci: nut El. The cam follower E5 isrectangular in cross section in one plane with a substantiallyrectilinear crest 24 as shown in Fig. 3 and has a face which issubstantially transversely convex in a plane at to the first mentionedplane, as shown in Fig. 4. The valve lifter it is operated by means of acam l8 carried by a camshaft 2i} and having a lobe 2?: which, due torotation of the camshaft, makes contact with the cam follower I6. Itwill be seen that the lobe 22 would contact the crest 2d of the camfollower so as to provide the effect of a flat face on the cam followerl6, as illustrated in Fig. 3, and contact will be made by the cam at aposition reached earlier in its rotation than the position where itcontacts the convex surface 25 in Fig. 4.

Referring now to Fig. 5, the valve lifter I4 is slidably mounted in abushing 28 which is pivotally mounted in a mounting plate 30 and thisbushing has an integral arm 32. The valve lifter 14 may, if desired, bebiased by a spring 34 mounted coaxially of the lifter i i and compressedbetween the bushing 28 and the follower I6. The valve lifter isprevented from rotating within the bushing 28 by means of a key 36slidin in a slot 38 in the bushing. It is obvious that by rotatin thebushing 28 by means of the arm 32, and thereby rotating the valvelifter, a different contour of the cam follower it may be brought intocontact with the cam l8.

Referring now to Fig. 2 it will be noted that this figure illustrated atwo cylinder internal combustion engine in which two inlet valves andtwo exhaust valves are operated by valve lifters of the type proposed bythis invention. The arms 32 of the bushings 28 are operatively linked.by means of a connecting bar 42 which in turn is connected to a suitablecontrol. In this way all the valve lifters may be rotated simultaneouslythus producing an equal change in timing of all the valves. With the camfollower 16 disposed to present the efiectively fiat contour orrectilinear crest 24 in contact with the cam the valve will open earlierand remain open for a longer period while with the cam follower disposedso that th transversely convex face 26 of the cam follower isefiectively in contact with the cam the valve opening will be slightlydelayed and the valve will beopen for a shorter period. Thus it will beSeen that t first described position of the cam follower will besuitable for high speed operation of the engine while the second namedposition of thecam follower will be more suited to slower speedoperation. It will be obvious that the use of a cam follower of the typedescribed is not limited to.

internal combustion engines but may be applied to any poppet type valvein other mechanisms such as compressors or the like.

The operation of this invention will be clearly comprehended from aconsideration of the foregoing description of the mechanical detailsthereof, taken in connection with the drawingiand the above recitedobjects. It will be obvious that all said objects are amply achieved bythis invention.

Further description would appear to be unnecessary.

It is understood that minor variation from the form or" the inventiondisclosed herein may be made without departure from the spirit and scopeof the invention, and that the specification and drawing are to beconsidered as merely illustrative rather than limiting.

I claim:

1. Variable timing valve operating means for use with poppet valves,comprising a valve lifter having a cam follower with a working facetransversely arcuate and having a rectilinear crest, said cam followerbeing rotatively adjustable about an axi normal to said crest, and meansholding the cam follower selectively in two positions angularly spaceddegrees, whereby the effects of an arcuate working face and a fiatworking face on said cam follower are alternatively obtained.

2. Variable timing Valve operating means for use with poppet valves,comprising a valve lifter having a cam vfollower with a working facetransversely convex and having a rectilinear crest, and

adjusting means for rotatively shifting said cam follower about an axisnormal to said crest, whereby the efiects of a convex and a fiat work-'ing face are alternatively obtained.

3, Variable timing valve operating means for use with poppet valves,comprising a valve lifter having a cam follower with a working facetransversely convex and having a rectilinear crest, and adjusting meansfor rotatively shifting said cam follower about an axis normal to saidcrest, whereby the effects of a convex and a hat working face arealternatively obtained, said adjusting means comprising a sleeve bushingfor said valve lifter, means preventing relative rotation of saidbushing and valve lifter while allowing relative axial movement, andmeans for rotatively adjusting said bushing and lifter about theircommon axis.

4. The combination of apparatus according to claim 3 with intake andexhaust valves, whereby said valves are simultaneously adjusted.

JAMES R. HUTCHISON.

Name Date Roof Sept. 23, 192

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